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Call for ContributionsHETEROCYCLES Special Issue Vol. 99 in honor of Professor Tohru Fukuyama on 70th Birthday

Submission deadline: September 10, 2018
On the occasion of Professor Tohru Fukuyama's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on April 1, 2019 as Vol. 99. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of May, 2018. Manuscript should reach the editorial office no later than September 10, 2018.
Contact: submit@heterocycles.com

March 5, 2018

Heterocycles Award
HETEROCYCLES is pleased to announce Heterocycles Award.
In recognition of an outstanding oral presentation at the 47th Congress of Heterocyclic ChemistrySee more

December 13, 2017

Call for ContributionsHETEROCYCLES Special Issue Vol. 97 in honor of Professor Kiyoshi Tomioka on 70th Birthday

Submission deadline: February 15, 2018
On the occasion of Professor Kiyoshi Tomioka's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on September 1, 2018 as Vol. 97. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of November, 2017. Manuscript should reach the editorial office no later than February 15, 2018.
Contact: submit@heterocycles.com

■ A Theoretical Study of the Structure and Tautomerism of 1,2,4,6-thiatriazine 1,1-Dioxide

Abstract

"Ab initio" theoretical Calculations have been used to study the structure and annular tautomerism of 2(4)H-1,2,4,6-thiatriazine 1,1-dioxide. The 4H-tautomer has been found to be the most stable in agreement with 1H-, 13C- and 15N-nmr data.

■ Molecular Yardsticks: Synthesis of Higher Homologs of 7,12-Dihydropyrido[3,4-b:5,4-b’]diindole. Probing the Dimensions of the Benzodiazepine Receptor Inverse Agonist Site

Krishnaswamy Narayanan and James M. Cook*

*Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, U.S.A.

Abstract

The synthesis of some of the higher homologs 7,12-dihydropyridodiindole 2, eg. diindoles 3, 4, 6, and 7, via a thermally induced Fischer indole cyclization of 1 with the appropriate naphthylhydrazines and quinolylhydrazines is described. These pyridodiindoles are to be used as molecular yardsticks in defining the spatial dimensions of the benzodiazepine receptor inverse agonist site.

■ Facile Synthesis of Tetrahydro-2-furylated Pyrimidines and Purines Using a New Catalyst of Cesium Chloride

Abstract

1-(Tetrahydro-2-furyl)pyrimidine and 9-(tetrahydro-2-furyl)purine derivatives were successfully synthesized in good yields by the reactions of trimethylsilylated pyrimidine and purine bases with 2-acetoxytetrahydrofuran using a new catalyst of cesium chloride in acetonitrile under mild conditions.

■ Alkylative Lactonization of γ,δ-Unsaturated Esters with α-Chloro Sulfides. A Concise Synthesis of the Monoterpene Lactone from Chrysanthemumflosculosum L.

Abstract

The γ,δ-unsaturated ester 1, on being treated with α-chloro sulfides 2 in the presence of SnCl4, underwent an alkylative lactonization to give the δ-lactones 3. This method was applied to the synthesis of the monoterpene lactone 4 isolated from Crysanthemumflosculosum L.

■ Reaction of Aryl Halides with (Z)-1-Ethoxy-2-tributylstannylethene: A Versatile Method for the Introduction of 2-Ethoxyethenyl Group into Aromatic Nuclei

Abstract

The reaction of 4-substituted bromobenzenes, except for 4-bromophenol and 4-bromoaniline, with (Z)-1-ethoxy-2-tributylstannylethene is well prompted by the catalytic action of dichlorobis(triphenylphosphine)palladium in dimethylformamide in the presence of tetraethylammonium chloride to give (Z)-1-ethoxy-2-(4-substituted phenyl)ethene. The method is also useful for the introduction of a 2-ethoxyethenyl moiety into heteroaromatic ring s such as pyridine, thiophene, indole.

■ Development of a Hydrazine-mediated System for the Reductive Activation of Mitomycin C

David J. Russell and Harold Kohn*

*Department of Chemistry, University of Houston, Houston, TX 77204-5641, U.S.A.

Abstract

The reactivity of mitomycin C (1) with hydrazines (2) has been examined. Monoarylhydrazines have been shown to efficiently reduce 1 leading to the activation of both proposed DNA binding sites (C-1 and C-10) within the drug.

Abstract

Chiral 3,5-disubstituted 4,5-dihydro-1,2,4-oxadiazoles (3, 4) have been prepared starting from benzamidoxime (1) and (R)-(-)-2,3-O-isoproppylideneglyceraldehyde (2). The structure of 3 was establised as (4’R)-5-(2’,2’-dimethyl-1’,3’-dioxolan-4’-yl)-3-phenyl-4,5-dihydro-1,2,4-oxadiazole by X-ray diffrection analysis on a single crystal. Mild possassium permanganate oxidationof a mixture of 3 and 4 gave the corresponding 1,2,4-oxadiazole (5).

Abstract

The natural coumarins ramosinin (1) and 3-(1’,1’-dimethylallyl)-8-(3",3"-dimethylallyl)xanthyletin (2) have been synthesized from umbelliferone. The synthesis of the angular derivatives 3-(1’,1’-dimethylallyl)columbianetin (9) and 3-(1’,1’-dimethylallyl)lomatin (10) was also achiebed.

Abstract

1,2,3,4-Tetrahydropyrido[2’,3’:4,5]imidazo[1,2-a]pyrimidin-2-ones 1 are synthesized from 3-amino-2-benzylaminopyridines by condensation with N-(3-chloropropanoyl)carbonimidic dichloride and subsequent cyclisation. 1,2,3,4-Tetrahydropyrido[2’,3’:4,5]imidazo[1,2-a]pyrimidin-2-ones 2 are prepared from methyl N-(3-amino-2-pyridyl)-3-aminopropanoates by condensation with N-acetylcarbonimidic dichloride, hydrolysis and cyclisation. Alkylation of pyridoimidazo[1,2-a]pyrimidin-2-ones 1 or 2 gives the corresponding 1-alkyl derivatives.

Abstract

4-Hydrazino-5-nitropyrimidine and its 6-methoxy derivative were condensed under heating with ethyl orthoformate to afford the title compounds through the intermediacy of an imino ether. In both cases the first formed 1,2,4-triazolo[4,3-c]pyrimidines were not isolated and directly converted to their [1,5-c] isomer by a Dimroth rearrangement.

■ Synthesis of (±)-Physovenine and (±)-7-Bromophysovenine from Intermediates of the Synthesis of Physostigmines

Abstract

Facile synthesis of (±)-physovenine (1) was accomplised from oxindole 3, an intermediate in Julian’s total synthesis of physostigmines (2A and 2B). C-Alkylation of 3 with methyl bromoacetate afforded ester 4 which was reduced with LAH in THF at 0 °C to directrly afford tetrahydrofuroindole 6. Ether cleavage of 6 with BBr3 in dichloromethane afforded phenol 7, and (±)-physovenine (1) on treatment of 7 with methyl isocyanate in ehter. Bromination of 1 with bromosuccinimide in methanol afforded (±)-7-bromophysovenine (8).

■ Reactivity of Substituted N-Aminopyridinium Salts and Their Benzologues. A Novel Approach to s-Triazolo[1,5-a]quinolinium and s-Triazolo[5,1-a]isoquinolinium Derivatives

Abstract

The reaction of 1-amino-2-cyanopyridinium perchlorate (1) with triethyl orthoformate gave an ethyl iminoformate derivative (2) which resulted in formation of a 1-iminopyrido-as-triazinium salt (3) in reaction with primary amine, and a formamidino derivative (4) with morpholine gave 2,3-diaza-1,3,5,7-octatetraene (5). The two benzologues of 1,N-aminoquinolinium (9) and N-aminoisoquinolinium (19) gave ethyl iminoformates (10 and 20) and formamidines (14 and 23). In reactions with primary amines these compounds led to s-triazolo[1,5-a]quinolinium (16) and [5,1-a]isoquinolinium (25) salts, respectively.

Abstract

The reaction of 2’-O-methanesulfonylerythromycin A derivatives (2) with a variety of nucleophilic reagents gave 2’-dimethylamino-3’-substituted derivatives (3). The reaction took place with neighboring group-participated nucleophilic substitution involoving migration of participating 3’-dimethylamino group. This migration was also observed in the case of N-oxide of the dimethylamino group.

Abstract

6-Purinemalononitrile (3), which was prepared by the substitution of 6-chloropurine (1) with malononitrile or deprotection of methoxymethyl group of (9-methoxymethyl-purin-6-yl)malononitrile (2) with acid, has been catalytically hydrogenated to the α-(aminomethylene)-6-purineacetonitrile (4). Substitution of 4 with hydrazine and acetamidine hydrochloride gave pyrazole derivative (7) and pyrimidine derivative (8), respectively.

Abstract

The introduction of chlorine atoms into aromatic rings of berbines was effected from an ethoxycarbamido group which does not undergo decomposition under the conditions of the Bischler-Napieralski reaction. At the end of he synthesis of the berbine ring system this group was transformed into a primary aromatic amine which was converted into chlorine by the Sandmeyer reaction. Thus berbines 6a,b chlorinated in the aromatic ring A and berbines 10a,b chlorinated in the aromatic ring D were prepared. The preparation of the starting β-phenethylamines 1a,b with an ethoxycarbamido group was also discussed.

Abstract

The (8aR,12aS,13aS)-decahydro-6H-isoquino[2,1-g][1,6]naphthyridine sulfonamides 1a,b were prepard from (+)-(3R,11bS)-3-cyanoethylhexahydrobenzo[a]quinolizinones 3a,b. These key intermediates were obtained by resolution of (±)-3a,b with (+)-camphorsulfonic acid in ethyl acetate accroding the the conditions used in the Openshaw-Whittaker synthesis of (-)-emitine.

■ Structure of Five New Prenylated Flavonoids L, M, N, O, and P from Aerial Parts of Glycyrrhiza uralensis

Abstract

Five new prenylated flavonoids were isolated from the aerial parts of Glycyrrhizauralensis FISCH. et DC. (Leguminosae), and the structures of the new compounds, gancaonins L, M, N, O, and P were elucidated as 8-prenylated 5,7,3’,4’-tetrahydroxyisoflavone, 8-prenylated 5,7-dihydroxy-8’-methoxyisoflavone, 6-prenylated 4’-methoxy-5,7,2’-trihydroxyisoflavone, 6-prenylated 5,7,3’,4’-tetrahydroxyflavone, and 6-prenylated 5,7,3’,4’-tetrahydroxyflavonol, respectively, on the basis of spectral evidence.